In wireless communication represented by wireless local area networks (LANs) conforming to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard series, there are many setting items that must be set prior to use.
For example, as setting items, there are communication parameters needed to perform wireless communication, such as the Service Set Identifier (SSID) which is a network identifier, an encryption method, an encryption key, an authentication method, and an authentication key. It is very complicated for the user of a wireless device to manually enter and set these communication parameters.
Therefore, various manufacturers have devised automatic setting methods for easily setting communication parameters in wireless devices.
In these automatic setting methods, one device (hereinafter called a providing apparatus) provides communication parameters to another device (hereinafter called a receiving apparatus) connected thereto, using a procedure and messages determined in advance between these connected devices, and accordingly the communication parameters are automatically set. Patent Citation 1 discloses an example of automatically setting communication parameters in wireless LAN ad-hoc mode communication (hereinafter called ad-hoc communication).
Also, Non Patent Citation 1 discloses an example of automatically setting communication parameters in wireless LAN infrastructure mode communication (hereinafter called infra-communication).
In the automatic setting method of Non Patent Citation 1, the role of a providing apparatus that provides communication parameters to another wireless device and the role of a receiving apparatus that receives the communication parameters provided by the providing apparatus and sets the communication parameters in the receiving apparatus are necessary.
Therefore, when a wireless device is to receive provided communication parameters by performing automatic setting, the wireless device must find a providing apparatus that provides communication parameters. To search for a providing apparatus, a probe request and a probe response which are search signals for a wireless LAN can be used. In this case, a receiving apparatus sends a probe request as a search message, and detects a providing apparatus by receiving, as a response from the providing apparatus, a probe response including information indicating that the sender of the response is a providing apparatus.
In infra-communication, an apparatus that sends a response to a probe request is an access point. Therefore, when an access point operates as a providing apparatus, a receiving apparatus that receives provided communication parameters can easily detect the providing apparatus.
In contrast, in ad-hoc communication, it is defined that an apparatus that sends a response to a probe request is an apparatus that sent a beacon immediately before receiving the probe request. Therefore, for example, when another apparatus is participating in a network where a providing apparatus is participating, this other apparatus may respond to a probe request from a receiving apparatus. As a result, it may take a longtime for the receiving apparatus to detect the providing apparatus. Furthermore, the receiving apparatus may not be able to detect the providing apparatus before the time limit of a communication-parameter automatic setting process expires. In this case, no communication-parameter automatic setting may be performed.
[Patent Citation 1]
US Patent Application No. 2006/0268744 (corresponding to Japanese Patent Laid Open No. 2006-311139)
[Non Patent Citation 1]
Wi-Fi CERTIFIED™ for Wi-Fi Protected Setup: Easing the User Experience for Home and Small Office Wi-Fi® Networks, http://www.wi-fi.org/wp/wifi-protected-setup